Cosmetic methods and compositions for conditioning human skin by topical application to the skin of cosmetic compositions containing carboxymethylates of branched alcohols, and/or ethoxylates thereof.
Sebum is skin oil which is produced by sebocytes (cells of the sebaceous glands in the skin) and is then secreted to the skin surface. A frequent and undesirable skin condition is xe2x80x9coily skin,xe2x80x9d the condition which results from the excessive amount of sebum on the skin. Oily skin is associated with a shiny, undesirable appearance and a disagreeable tactile sensation and affects various age groups. Therefore, cosmetic products which provide both sebum control and anti-aging benefits are highly desirable.
The prior art discloses branched alcohols as compounds which provide skin benefits such as sebum suppression. For example, U.S. Pat. No. 5,756,109 issued to Burger et al. (hereinafter xe2x80x9cBurger ""109xe2x80x9d) teaches the use of a noncylic polyunsaturated diterpene alcohol, geranyl geraniol, in combination with a retinol as a skin conditioning composition. Burger ""109 discloses sebum suppression as one advantage of the branched alcohol in combination with retinol. U.S. Pat. No. 5,344,850 issued to Hata et al. discloses topical compositions containing C18 saturated or unsaturated alcohol with four methyl branches for treating or preventing acne.
A problem exists in that branched alcohols alone inherently possess an unpleasant odor, characteristic of vinyl or a xe2x80x9cnew car smell,xe2x80x9d making application in cosmetic skin conditioning compositions highly undesirable. Moreover, branched alcohols themselves are water-insoluble.
Derivatives of branched alcohols have also been disclosed in the prior art for a variety of uses, such as personal cleansing compositions. For example, WO 9918928 assigned to The Proctor and Gamble Company, discloses personal cleansing compositions comprising branched surfactant systems having a hydrophobic group and a hydrophilic group. The hydrophobic group comprises mid-chain branched and linear surfactant compounds. The hydrophilic group is selected from the group consisting of sulfate and/or ethoxylates thereof.
U.S. Pat. No. 3,992,443 issued to Springmann (hereinafter xe2x80x9cSpringmann ""443xe2x80x9d) discloses a process for the carboxymethylation of alcohols or ether alcohols in a single stage. Springmann ""443 teaches the use of both straight chain and branched alcohols as suitable starting alcohols.
U.S. Pat. No. 6,020,303 issued to Cripe et al. (hereinafter xe2x80x9cCripe ""303xe2x80x9d) discloses detergent surfactant compositions derived from mid-chain branched primary alkyl hydrophobic groups and hydrophilic groups. Specifically, Cripe ""303 discloses alkyl sulfates for application in laundry and cleaning compositions.
U.S. Pat. No. 5,093,112 issued to Birtwistle et al. discloses topical cleansing (detergent) compositions containing an alcohol and an alkyl or alkenyl phosphate salt.
The prior art cited above does not seem to suggest or disclose cosmetic compositions or methods for skin conditioning which avoid the negative characteristics of branched alcohols. Therefore, a need remains for cosmetic compositions that retain the beneficial effects of branched alcohols in relation to sebum suppression and skin conditioning while avoiding the unpleasant odor and water-insolubility associated with such alcohols.
The present invention includes a skin care cosmetic composition comprising:
(i) from about 0.001% to about 50% of a compound of the formula A:
Rxe2x80x94Oxe2x80x94Mxe2x80x83xe2x80x83(A)
xe2x80x83wherein:
R is a branched alkyl chain having at least 9 carbon atoms, generally from 9 to 15 atoms, and at least two branches;
O is an oxygen atom; and
M is (xe2x80x94CH2CO2X) or (xe2x80x94(CH2CH2O)nxe2x80x94CH2CO2X) and mixtures thereof, where n is an integer of at least 1 and X is hydrogen or a cation; and
(ii) a cosmetically acceptable vehicle.
The present invention also includes a cosmetic method of controlling or preventing an oily skin condition, especially in the facial area, by applying to the skin the inventive composition.
The invention also includes a cosmetic method of reducing, preventing or controlling sebum secretion from sebocytes by applying the inventive composition.
The invention also includes a cosmetic method of stimulating collagen synthesis by fibroblasts in the skin, by applying to the skin the inventive composition. The inventive methods and compositions provide control of sebum secretion from sebocytes, improved oil control and improved skin feel, and prevent shine and stickiness, while also providing anti-aging benefits which results in reduced appearance of wrinkles and aged skin, improved skin color, treatment of photoaged skin, improvement in skin""s radiance and clarity and finish, and an overall healthy and youthful appearance of the skin.
Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word xe2x80x9cabout.xe2x80x9d All amounts are by weight of the oil-in-water emulsion, unless otherwise specified.
The term xe2x80x9cskinxe2x80x9d as used herein includes the skin on the face, neck, chest, back, arms, hands, legs and scalp.
The inventive methods and compositions include a carboxymethylate of a branched alcohol, and/or ethoxylates thereof (hereinafter xe2x80x9ccompound Axe2x80x9d), and are of the general formula A:
Rxe2x80x94Oxe2x80x94Mxe2x80x83xe2x80x83(A)
wherein:
R is a branched alkyl chain having at least 9 carbon atoms, generally from 9 to 15 atoms, and at least two branches;
O is an oxygen atom; and
M is (xe2x80x94CH2CO2X) or (xe2x80x94(CH2CH2O)nxe2x80x94CH2CO2X) and mixtures thereof,
where n is an integer of at least 1 and X is hydrogen or a cation. The cation may be selected from the group consisting of sodium, lithium, potassium, calcium, magnesium, manganese and amines including quartenary alkyl amines, but is not limited thereto.
The branched alkyl chain of the present invention is derived from a branched alcohol having at least 9 carbon atoms and at least two branches, as noted above. As seen in Example 1 discussed infra, alcohols with less than 9 carbons do not aid in collagen synthesis. The preferred alcohols from which the inventive compositions are derived contain a total of at least 10 carbon atoms in order to obtain maximum efficacy. The most preferred alcohols from which the inventive compositions are derived, contain from 2 to 5 branches, in order to maximize efficacy at minimum cost. Preferably, the branches are methyl branches, due to commercial availability. The alcohol may contain a mix of various chain lengths"" alcohols. Such mixed alcohol is suitable in deriving the inventive compositions, as long as the predominant alcohol in the mix contains a total of at least 9 carbon atoms and at least two branches.
Carboxymethylation of the branched alcohol involves the addition of a carboxyl group to the branched alcohol. Compound A is derived from alcohols which are commercially available, e.g. from Exxon or Henkel. Ethoxylation involves first directly adding an ethylene oxide to the branched alcohol, followed by carboxymethylation.
The salt forms of compound A (where M is a cation in formula A) are preferred because they provide a neutral pH for the inventive compositions before application to the skin to avoid irritation. Moreover, the salts dissociate upon contact with the skin to release the beneficial characteristics of the anionic nature of the inventive compositions. Preferably, sodium salt is used because of commercial availability.
Compound A of the present invention retains the beneficial sebum suppression qualities of branched alcohols while eliminating the unpleasant odor. Moreover, compound A is an anionic surfactant, thus providing a negative charge that aids in binding the surfactant onto the skin""s surface. The water soluble characteristic effectuates delivery into the skin. Moreover, as compared to prior art surfactants such as sulfate groups on branched alcohols, the carboxyl group in compound A is a better metal chelator and milder to the skin due to its relatively low acidity (pKa of approximately 3). The carboxyl group has a lower molecular weight than a sulfate group, thus lower amounts of the carboxyl group will yield more beneficial results than the sulfate group.
Compound A is employed in the inventive methods and compositions in an amount of from 0.001% to about 50%, preferably from 0.1% to 20%, most preferably from 0.1% to 10%.
The inventive compositions containing compound A may also include a retinoid. Retinoids increase collagen synthesis by dermal fibroblasts. This results in protection from sun damage and smoothening of wrinkled skin. Addition of retinoids to compound A provided improved inhibition of lipogenesis as well as increased collagen synthesis in comparison to compound A alone. The term xe2x80x9cretinoidsxe2x80x9d as used herein includes retinoic acid, retinol, retinal, and retinyl esters. Included in the term xe2x80x9cretinoic acidxe2x80x9d are 13-cis retinoic acid and all-trans retinoic acid.
The term xe2x80x9cretinolxe2x80x9d as used herein includes the following isomers of retinol: all-trans-retinol, 13-cis-retinol, 11-cis-retinol, 9-cis-retinol, 3,4-didehydro-retinol. Preferred isomers are all-trans-retinol, 13-cis-retinol, 3,4-didehydro-retinol, 9-cis-retinol, 9-cis-retinol. Most preferred is all-trans-retinol, due to its wide commercial activity.
Retinyl ester is an ester of retinol. The term xe2x80x9cretinolxe2x80x9d has been defined above. Retinyl esters suitable for use in the present invention are C1-C30 esters of retinol, preferably C2-C20 esters, and most preferably C2, C3, and C6 esters because they are more commonly available. Examples of retinyl esters include but are not limited to: retinyl palmitate, retinyl formate, retinyl acetate, retinyl propionate, retinyl butyrate, retinyl valerate, retinyl isovalerate, retinyl hexanoate, retinyl heptanoate, retinyl octanoate, retinyl nonanoate, retinyl decanoate, retinyl undecandate, retinyl laurate, retinyl tridecanoate, retinyl myristate, retinyl pentadecanoate, retinyl heptadeconoate, retinyl stearate, retinyl isostearate, retinyl nonadecanoate, retinyl arachidonate, retinyl behenate, retinyl linoleate, retinyl oleate, retinyl lactate, retinyl glycolate, retinyl hydroxy caprylate, retinyl hydroxy laurate, retinyl tartarate.
The retinoids in the present invention are present in an amount of from 0.001% to 10%, preferably from 0.01% to 1%, and most preferably from 0.01% to 0.05%.
Compound A employed in the inventive methods and compositions is liquid, and thus the invention is effective even in the absence of the carrier. However, the compositions according to the invention comprise a cosmetically acceptable vehicle to act as a diluant, dispersant or carrier of compound A thereof, so as to facilitate their distribution when the composition is applied to the skin.
The vehicle may be aqueous, anhydrous or an emulsion. Preferably, the compositions are aqueous or an emulsion, especially water-in-oil or oil-in-water emulsion. Water when present will be in amounts which may range from 5 to 99%, preferably from 40 to 90%, optimally between 60 and 90% by weight.
Besides water, relatively volatile solvents may also serve as carriers within compositions of the present invention. Most preferred are monohydric C1-C3 alkanols. These include ethyl alcohol, methyl alcohol and isopropyl alcohol. The amount of monohydric alkanol may range from 1 to 70%, preferably from 10 to 50%, optimally between 15 and 40% by weight.
Emollient materials may also serve as cosmetically acceptable carriers. These may be in the form of silicone oils and synthetic esters. Amounts of the emollients may range anywhere from 0.1 to 50%, preferably between 1 and 20% by weight.
Silicone oils may be divided into the volatile and non-volatile variety. The term xe2x80x9cvolatilexe2x80x9d as used herein refers to those materials which have a measurable vapor pressure at ambient temperature. Volatile silicone oils are preferably chosen from cyclic or linear polydimethylsiloxanes containing from 3 to 9, preferably from 4 to 5, silicon atoms. Linear volatile silicone materials generally have viscosities less than about 5 centistokes at 25xc2x0 C. while cyclic materials typically have viscosities of less than about 10 centistokes. Nonvolatile silicone oils useful as an emollient material include polyalkyl siloxanes, polyalkylaryl siloxanes and polyether siloxane copolymers. The essentially non-volatile polyalkyl siloxanes useful herein include, for example, polydimethyl siloxanes with viscosities of from about 5 to about 25 million centistokes at 25xc2x0 C. Among the preferred non-volatile emollients useful in the present compositions are the polydimethyl siloxanes having viscosities from about 10 to about 400 centistokes at 25xc2x0 C.
Among the ester emollients are:
(1) Alkenyl or alkyl esters of fatty acids having 10 to 20 carbon atoms. Examples thereof include isoarachidyl neopentanoate, isononyl isonanonoate, oleyl myristate, oleyl stearate, and oleyl oleate.
(2) Ether-esters such as fatty acid esters of ethoxylated fatty alcohols.
(3) Polyhydric alcohol esters. Ethylene glycol mono and di-fatty acid esters, diethylene glycol mono- and di-fatty acid esters, polyethylene glycol (200-6000) mono- and di-fatty acid esters, propylene glycol mono- and di-fatty acid esters, polypropylene glycol 2000 monooleate, polypropylene glycol 2000 monostearate, ethoxylated propylene glycol monostearate, glyceryl mono- and di-fatty acid esters, polyglycerol poly-fatty esters, ethoxylated glyceryl monostearate, 1,3-butylene glycol monostearate, 1,3-butylene glycol distearate, polyoxyethylene polyol fatty acid ester, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters are satisfactory polyhydric alcohol esters.
(4) Wax esters such as beeswax, spermaceti, myristyl myristate, stearyl stearate and arachidyl behenate.
(5) Sterols esters, of which cholesterol fatty acid esters are examples thereof.
Fatty acids having from 10 to 30 carbon atoms may also be included as cosmetically acceptable carriers for compositions of this invention. Illustrative of this category are pelargonic, lauric, myristic, palmitic, stearic, isostearic, hydroxystearic, oleic, linoleic, ricinoleic, arachidic, behenic and erucic acids.
Humectants of the polyhydric alcohol type may also be employed as cosmetically acceptable carriers in compositions of this invention. The humectant aids in increasing the effectiveness of the emollient, reduces scaling, stimulates removal of built-up scale and improves skin feel. Typical polyhydric alcohols include glycerol, polyalkylene glycols and more preferably alkylene polyols and their derivatives, including propylene glycol, dipropylene glycol, polypropylene glycol, polyethylene glycol and derivatives thereof, sorbitol, hydroxypropyl sorbitol, hexylene glycol, 1,3-butylene glycol, 1,2,6-hexanetriol, ethoxylated glycerol, propoxylated glycerol and mixtures thereof. For best results the humectant is preferably propylene glycol or sodium hyaluronate. The amount of humectant may range anywhere from 0.5 to 30%, preferably between 1 and 15% by weight of the composition.
Thickeners may also be utilized as part of the cosmetically acceptable carrier of compositions according to the present invention. Typical thickeners include crosslinked acrylates (e.g. Carbopol 982), hydrophobically-modified acrylates (e.g. Carbopol 1382), cellulosic derivatives and natural gums. Among useful cellulosic derivatives are sodium carboxymethylcellulose, hydroxypropyl methylcellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, ethyl cellulose and hydroxymethyl cellulose. Natural gums suitable for the present invention include guar, xanthan, sclerotium, carrageenan, pectin and combinations of these gums. Amounts of the thickener may range from 0.0001 to 5%, usually from 0.001 to 1%, optimally from 0.01 to 0.5% by weight.
Collectively, the water, solvents, silicones, esters, fatty acids, humectants and/or thickeners will constitute the cosmetically acceptable carrier in amounts from 1 to 99.9%, preferably from 80 to 99% by weight.
An oil or oily material may be present, together with an emulsifier to provide either a water-in-oil emulsion or an oil-in-water emulsion, depending largely on the average hydrophilic-lipophilic balance (HLB) of the emulsifier employed.
Various types of additional active ingredients may be present in cosmetic compositions of the present invention. Actives are defined as skin benefit agents other than emollients and other than ingredients that merely improve the-physical characteristics of the composition. Although not limited to this category, general examples include additional anti-sebum ingredients such as talcs and silicas, and sunscreens.
Sunscreens include those materials commonly employed to block ultraviolet light. Illustrative compounds are the derivatives of PABA, cinnamate and salicylate. For example, avobenzophenone (Parsol 1789(copyright)) octyl methoxycinnamate and 2-hydroxy-4-methoxy benzophenone (also known as oxybenzone) can be used. Octyl methoxycinnamate and 2-hydroxy-4-methoxy benzophenone are commercially available under the trademarks, Parsol MCX and Benzophenone-3, respectively. The exact amount of sunscreen employed in the compositions can vary depending upon the degree of protection desired from the sun""s UV radiation.
Many cosmetic compositions, especially those containing water, must be protected against the growth of potentially harmful microorganisms. Preservatives are, therefore, necessary. Suitable preservatives include alkyl esters of p-hydroxybenzoic acid, hydantoin derivatives, propionate salts, and a variety of quaternary ammonium compounds. Particularly preferred preservatives of this invention are methyl paraben, propyl paraben, phenoxyethanol and benzyl alcohol. Preservatives will usually be employed in amounts ranging from about 0.1% to 2% by weight of the composition.
The composition according to the invention is intended primarily as a product for No topical application to human skin, especially as an agent for controlling or preventing excessive sebum secretion.
In use, a quantity of the composition, for example from 1 to 100 ml, is applied to exposed areas of the skin, from a suitable container or applicator and, if necessary, it is then spread over and/or rubbed into the skin using the hand or fingers or a suitable device.
Product Form and Packaging:
The cosmetic skin composition of the invention can be in any form, e.g. formulated as a toner, gel, lotion, a fluid cream, or a cream. The composition can be packaged in a suitable container to suit its viscosity and intended use by the consumer. For example, a lotion or fluid cream can be packaged in a bottle or a roll-ball applicator or a propellant-driven aerosol device or a container fitted with a pump suitable for finger operation. When the composition is a cream, it can simply be stored in a non-deformable bottle or squeeze container, such as a tube or a lidded jar. The invention accordingly also provides a closed container containing a cosmetically acceptable composition as herein defined.
The composition may also be included in capsules such as those described in U.S. Pat. No. 5,063,057, incorporated by reference herein.